Mark Watson was hospitalised some months ago with anxiety-related chest pains, and instructed to de-stress. He has got a funny way of going about it: this year's Fringe finds him performing a stand-up show about the incident in the biggest theatre he has ever played. Mind you, that is no cause for worry: the Mock the Week star's Tigger-ish persona could power theatres twice as large as the 750-seat Pleasance Grand. The problem tonight is that his material doesn't fill his allotted hour. The Watson shtick is as funny as ever, but the show is thinner on substance than those that marked his recent, meteoric rise.

Doctors told Watson he should learn to see life as more of a joke. That ought to be a cinch for a stand-up, but Watson - with his loser's Welsh accent, every bit the classic mouse-that-roared comic - gets easily wound up. What's with that new brand of razor, the Gillette Stealth? "It's your hand attached to your body, shaving your face in your bathroom mirror. How fucking stealthy can it be?" Here, we see him vexed by hen parties, agitated by British train travel, and losing his rag in a Travelodge at a noisy party next door.

The guilty pleasure Watson takes in his rages is as delightful as ever. Witness the railway station set-piece in which a pigeon flies into a man's face, which Watson orchestrates as if directing a movie. He ought to turn the same dramatic eye on his show as a whole; it lacks structure and shape. But otherwise, there is not much for him to fret about. As for the audience, if seeing life as a joke helps beat stress, Watson's crowd must be the most chilled-out in Edinburgh.